The invention relates to a surgical stapling instrument, which can be used, e.g., in the diagnosis and therapy of all pathologies best treated by a curved stapled resection. It provides a means to extend the transluminal exploitation of mechanical suturing devices introduced via the anal canal, mouth, stomas, and service accesses. The treatment of rectal pathologies will be described as most frequent, but not only use of the invention.
The current transanal surgical procedure of choice is Transanal Endoscopic Microsurgery, which, however is burdened with difficulty of execution and complications such as dehiscence and abscesses. Current endoscopic excisions of, e.g., peduncular polyps usually do not allow necessary histological examination. This is of particular concern when the sample turns out to be malignant and the site is no longer visible during follow-up surgery. In the case of sessile polyps, the endoscopic excision presents similar drawbacks, and in addition difficulties in retrieving the sample, a related high loss of blood, and a risk of perforation of the intestinal wall. Traditional surgical excisions, for example via Transanal Endoscopic Microsurgery, are complicated and involve the intraluminal dissemination of neoplastic cells.
WO 97/47231 discloses an endoscopic stapler including a stapling head which is removably located on the distal end of an endoscope. The stapling head includes a stationary part, which houses a removable staple cartridge, and a movable part which includes an anvil for receiving and bending the ends of staples fired from the staple cartridge. The stationary part has a circular cross-sectional area, but the staples are arranged in two semi-circular rows, in which the staples are staggered relative to each other. The cross-sectional shape of the anvil is semi-circular, generally matching the rows of staples. After tissue to be excised has been clamped by moving the anvil towards the stationary part, the staples are consecutively expelled from the staple cartridge, and a knife cuts the tissue to be excised by moving along a staple line. Since the access for manipulating the tissue in order to place it correctly in between the anvil and the stationary part is somewhat obstructed by the cross-sectional shape of the stationary part, a remote-controlled forceps device is provided in the region of the staples and the anvil.
In U.S. Pat. No. 5,355,897, a surgical stapler is shown which derives from the well-known circular staplers for performing an anastomosis. In order to enable the local excision of tissue by means of this instrument, instead of a circular anastomosis, a shield extending around part of the periphery of the stapling region prevents unwanted tissue from entering the head of the device. A similar instrument is known from U.S. Pat. No. 5,360,154. In both cases, the region between the anvil and the staple cartridge is not easily accessible.
Surgical staplers comprising a staple cartridge having one or more straight rows of staples and a cutting blade running in parallel to the staples are disclosed in U.S. Pat. Nos. 4,665,916 and 4,881,545. In these instruments, tissue to be stapled and excised can be clamped between the staple cartridge and an anvil which is pivotally connected to the staple cartridge at one of its ends. Staplers having straight rows of staples, in which the staple cartridge can be moved in parallel relationship with respect to a stationary anvil in order to clamp the tissue to be stapled and excised, are known from U.S. Pat. Nos. 4,527,724, 5,137,198, and 5,605,272; these staplers are not provided with an automated cutting device. Generally, in many applications, straight staplers are not anatomically correct, i.e. straight staple lines do not fit a circular lumen contour.
U.S. Pat. No. 4,617,928 discloses a surgical instrument for Practising mechanical sutures and biopsies. This instrument comprises a fixed anvil and a staple cartridge (including a knife), which can be moved towards the anvil in order to clamp tissue between the anvil and the staple cartridge. In one embodiment, there are two staple rows arranged in a V-shaped configuration around a V-shaped knife. In another embodiment, an approximately semi-circular double row of staples surrounds an approximately semi-circular knife. In this embodiment, which is designed for practising pulmonary biopsies, free access to the inner faces of the cartridge and the anvil is hindered by an arm supporting the cartridge.
The object of the present invention is to provide an economical surgical stapling instrument for stapling (and optionally resecting) tissue, in particular inside the digestive track, which can be operated and used in a safe, effective, and fast manner.
This problem is solved by a surgical stapling instrument having the features of claim 1. Advantageous versions of the invention follow from the dependent claims.
The surgical stapling instrument according to the invention comprises a frame having a body portion and a handle extending from the body portion in the proximal end region of the instrument. A staple fastening assembly is mounted in the distal end region of the instrument. Here and in the following, the terms xe2x80x9cproximalxe2x80x9d and xe2x80x9cdistalxe2x80x9d relate to the user as reference, which means that the parts of the instrument close to the user under normal operating conditions are designated as xe2x80x9cproximalxe2x80x9d.
The staple fastening assembly includes a curved cartridge, which comprises at least one curved open row of staples, and, at the distal end of the instrument, a curved anvil, which is adapted to cooperate with the cartridge for forming the ends of the staples exiting from the cartridge. The staple forming plane of the anvil is arranged transversally with respect to the longitudinal axis of the body portion of the instrument. The staple fastening assembly is adapted to allow unobstructed access towards the concave inner faces of the cartridge and the anvil and thus to the tissue to be resected.
A cartridge moving device is adapted to move the cartridge essentially in parallel relationship towards the anvil from a spaced position for positioning tissue therebetween to a closed position for clamping the tissue. The staples can be driven out of the cartridge towards the anvil by means of a staple driving device.
Herein, the term xe2x80x9cstaplexe2x80x9d is used in a very general sense. It includes metal staples or clips, but also surgical fasteners made of synthetic material and similar fasteners. Synthetic fasteners usually have a counterpart (retainer member) held at the anvil. In this sense, the terms xe2x80x9canvilxe2x80x9d and xe2x80x9cstaple forming planexe2x80x9d also have a broad meaning which includes, in the case of two-part synthetic fasteners, the anvil-like tool and its plane where the retainer members are held, and similar devices.
Preferably, a knife is contained within the cartridge and is positioned such that there is at least one row of staples on at least one side of the knife. The knife is moved towards the anvil by means of a knife actuating device. If the stapling instrument does not include a knife, tissue to be resected after stapling can be cut by means of a separat surgical instrument.
The main advantage of the surgical stapling instrument according to the invention is its ability to allow endoluminal tissue resections and stapling through direct vision. Additionally, separate optics (e.g., an endoscope) can be used as an option. When the instrument is introduced into, e.g., the anal canal, free view onto and access to the site of the tissue to be resected is not obstructed by any parts of the instrument. The tissue to be excised can be pulled into the area in between the anvil and the cartridge, when the cartridge is in a spaced or open position, by means of a separate gripping instrument. Because of the unobstructed access towards the concave inner faces of the cartridge and the anvil, the gripping instrument can be used easily, effectively and safely. Afterwards, the cartridge is moved towards the anvil in order to clamp the tissue. A particular advantage is that the surgeon can well observe the clamping procedure when the movable cartridge approaches the resting anvil. When the cartridge has reached the closed position, the surgeon can xe2x80x9cfirexe2x80x9d the instrument, which means that the staples are driven out of the cartridge, penetrate the tissue, whereupon their ends are bent by the anvil, and the knife is moved towards the anvil in order to cut the tissue. When the instrument is retracted, the completely excised tissue stays in the staple fastening assembly and can thus be safely removed from the patient""s body.
The surgical stapling instrument according to the invention allows, e.g., the removal of a peduncular polyp and surrounding mucosa for optimal histological examination. Moreover, a valuable trace in the form of staples is left in the patient""s body which allows to find the site of the operation at a later time easily if a subsequent examination is required. In the case of sessile polyps, the advantages of the instrument are the rapid deployment of sterile sealing means (i.e. staples) and a low blood loss. Optimal histological examination results are possible because a good definition of possible muscular and perirectal infiltration of neoplastic cells is allowed. In the case of benign polyps and early diagnosed rectal cancer, the surgical procedure can be considered curative.
Examples for other applications of the surgical stapling instrument according to the invention are the treatment of mucosa prolapses of the rectum, rectoceles, anterior prolapses of the rectum, rectal prolapses, rectal ulcers, stenoses (e.g., at an anastomic site), Meckel diverticulum, esophageal pathologies, the transrectal stapling of trauma wounds, the intussusception of the rectum, and the resection of polyps via service enterotomy.
Preferably, the outer faces of the cartridge and the anvil are ergonomically shaped to match the anatomy of the internal lumen of the digestive track. The cartridge and the anvil can have a generally arc-like shape in the cross-sectional plane, the arc extending over an angle in the range 90xc2x0 to 270xc2x0.
In an advantageous version, the staple fastening assembly includes a curved guide portion, wherein the cartridge is mounted for movement between the distal end of the guide portion and the anvil. Preferably, the shape of the guide portion is arc-like in the cross-sectional plane and is similar to that of the cartridge and the anvil, allowing an unobstructed access towards the concave inner face of the guide portion as well. Preferably, the guide portion and the anvil are rigidly connected by means of at least one arm extending from at least one end of the anvil and generally running in parallel to the longitudinal axis of the body portion of the instrument. This arm does not interfere with surgical instruments used for manipulating the tissue to be excised and does not block the surgeon""s view. A staple fastening assembly designed in this way greatly facilitates the surgical applications of the instrument.
In an advantageous embodiment, there is at least one row of staples on each side of the knife. The advantage of this arrangement is that the tissue is safely held on both sides of the knife when the knife cuts the tissue, thus ensuring a clean excision of the tissue. Another advantage is that hemostasis of the resected site is maintained during the procedure. The staples sticking in the excised tissue are removed from the patent""s body together with that tissue specimen.
The distance between the cartridge and the anvil in the closed position is preferably adjustable. For example, the cartridge moving device can comprise an adjustable stop in order to prevent the cartridge from moving beyond the stop position and from clamping the tissue too much. Or a series of cartridges with different built-in tissue stops can be used according to the tissue thickness. It is also conceivable to use a series of cartridges which have different longitudinal dimensions which are adapted to the desired distance between the cartridge and the anvil in the closed position. By adjusting the distance between the cartridge and the anvil in the closed position, the instrument can be matched to the thickness and type of tissue to be excised.
In an advantageous version, the staple driving device is adapted to simultaneously drive the staples out of the cartridge towards the anvil, and the knife actuating device is adapted to cause the knife to protrude from the cartridge after the staple points have been driven out of the cartridge. In this design, pre-ferably the staple driving device and the knife actuating device are mechanically coupled for operation via a common trigger. This way of controlling the operation of the staples and the knife ensures a well-defined and clean cutting line in the tissue, while the handling is easy.
Preferably, the cartridge is removable so that a used cartridge without staples can be replaced with a fresh one, if required. This is particularly advantageous if the instrument is to be used several times during the same surgical procedure. It is also conceivable to design the instrument as a re-usable instrument which is sterilized after each surgical procedure. In this case, a fresh and sterile cartridge can be inserted during the next surgical procedure.
When the cartridge is removable, it can be mounted, e.g., in a cartridge holder which embraces the cartridge along the periphery of an arc-like shape in the cross-sectional plane. This design still allows an unobstructed access towards the concave inner face of the cartridge, i.e. up to the concave inner face of the cartridge holder, which matches the shape of the cartridge in the cross-sectional plane.
In another advantageous version, the knife is removable. This allows the selection of a knife of given dimensions or cutting properties, which is optimized to the surgical procedure in question, e.g., to the timing required when the staples penetrate the tissue and the tissue is cut, or simply a replacement of the knife if desired.
Preferably, the cartridge moving device includes a trigger lever (preferably close to the handle) for actuating the movement of the cartridge. Alternatively, the cartridge moving device can include a threaded shaft which is mounted in the body portion and coupled to a rotatable knob. In this case, the longitudinal movement of the cartridge for approaching the anvil is activated by rotating the knob. Mechanisms for effecting these kinds of movements are generally known in the prior art, see, e.g., U.S. Pat. No. 4,527,724.
Preferably, the anvil has an atraumatically shaped distal end region, which facilitates, e.g., the insertion of the instrument into the rectum and the advancement of the instrument inside the lumen.
In an advantageous embodiment of the invention, the staple fastening assembly is removably mounted in the distal end region of the body portion. This allows the frame of the instrument and many parts of the cartridge moving device, the staple driving device and the knife actuating device to be designed as re-usable components, which are sterilized after each surgical procedure, whereas the staple fastening assembly can be replaced after each surgical procedure.
In the following, some advantages of the surgical stapling instrument according to the invention are summarized: It is possible to perform a surgical procedure under local anaesthetics or spinal sedation. Generally, the procedures are fast and relatively easy. The blood loss tends to be low. It is possible to apply sterile staples in a septic field, which reduces the incidence of dehiscence and abscesses. Tumors with a diameter of up to about 3 cm can be excised. It is possible to identify the type of locally advanced tumors and to determine the tumor xe2x80x9cTxe2x80x9d level because the tumor site is visible when the instrument is used and the excised tissue can be safely removed by means of the instrument for pathological examination. Moreover, possible mucosa or muscular infiltration can be identified (in the case of lower carcinomas, the infiltration stage is a useful tool in the decision to proceed with anterior resection or amputation). The surgical site where the staples have been left behind can be quickly identified, e.g., by using X-rays. The instrument provides the ability to remove advanced growing or stenotic rectal neoplasias via a minimal invasive approach in poor condition patients for which a radical procedure is not indicated. It is also conceivable to use the instrument as a suturing device after the completion of a transanal endoscopic microsurgery.
Moreover, the instrument can be used as a distal stump suturing device in the lower anterior resection when a double stapling technique is performed. To this end, the instrument allows rectal stump closure with the instrument introduced via a laparoscopic approach. The instrument also allows an improved rectal stump closure, which is useful because it eliminates the xe2x80x9cDog Earsxe2x80x9d effect after colorectal anastomosis. Finally, the instrument allows the sealing of the specimen with a line of staples.
The surgical stapling instrument according to the invention can be even used for the excision of tumors larger than 3 cm. In this case, tissue wall mobilization is required, which can be achieved via a laparoscopic approach, via an anterior perineal access for the anterior wall, or via a posterior perineal access for the posterior wall and multiple applications of the reloadable device (i.e. of the instrument having the cartridge replaced after each firing of staples out of several actuations).